package com.atguigu.gulimall.product.service.impl;

import com.atguigu.common.utils.PageUtils;
import com.atguigu.common.utils.Query;
import com.atguigu.gulimall.product.dao.CategoryDao;
import com.atguigu.gulimall.product.entity.CategoryEntity;
import com.atguigu.gulimall.product.service.CategoryService;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import org.springframework.stereotype.Service;

import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;


@Service("categoryService")
public class CategoryServiceImpl extends ServiceImpl<CategoryDao, CategoryEntity> implements CategoryService {

    @Override
    public PageUtils queryPage(Map<String, Object> params) {
        IPage<CategoryEntity> page = this.page(
                new Query<CategoryEntity>().getPage(params),
                new QueryWrapper<CategoryEntity>()
        );

        return new PageUtils(page);
    }

    @Override
    public List<CategoryEntity> listWithTree() {

        //1，查出所有分类
        List<CategoryEntity> entities = baseMapper.selectList(null);

        //2，组装成父子的树形结构
        List<CategoryEntity> level1Menus =  entities.stream().filter((categoryEntity) ->
             categoryEntity.getParentCid().longValue() == 0
        ).map((menu)->{
            menu.setChildren(getChildrens(menu,entities));
            return menu;
        }).sorted((menu1,menu2)->{
            return (menu1.getSort()==null?0:menu1.getSort()) - (menu2.getSort()==null?0:menu2.getSort());
        }).collect(Collectors.toList());

        return level1Menus;
    }

    //递归查找所有菜单的子菜单
    private List<CategoryEntity> getChildrens(CategoryEntity root, List<CategoryEntity> all) {

        List<CategoryEntity> chilldren =
        // 1，首先是讲集合转成流 使用过滤方法 找出当前父菜单所有的子菜单
                all.stream().filter(categoryEntity -> {
            return categoryEntity.getParentCid().longValue() == root.getCatId().longValue();

        // 2，循环过滤后的数据 递归调用当前方法 设置子菜单的所有子菜单 并把数据设置回来
        }).map(categoryEntity -> {
            categoryEntity.setChildren(getChildrens(categoryEntity,all));
            return categoryEntity;

        // 3，排序方法 排序规则的编写 sort值越小越在前
        }).sorted((menu1,menu2)->{
            return (menu1.getSort()==null?0:menu1.getSort()) - (menu2.getSort()==null?0:menu2.getSort());

        // 4，转成集合返回
        }).collect(Collectors.toList());

        return chilldren;
    }


}